Published reports of CH 4 yields as g CH 4/kg dry matter (DM) intake suggest that emissions from sheep fed fresh forage chicory ( Cichorium intybus) are about 30% lower than from those fed fresh ryegrass. In this study, 2 year old wethers (16; 543.8 kg liveweight) were fed either mature chicory or perennial ryegrass at 1.3 times maintenance metabolisable energy requirements in the late spring/early summer of 2009. Methane emissions were determined using individual animal respiration chambers. Feeds differed in their chemical composition with chicory containing 856 g/kg organic matter (OM), 117 g/kg crude protein (CP) and 281 g/kg neutral detergent fibre (aNDF), whereas ryegrass contained 916 g/kg OM, 85 g/kg CP and 499 g/kg aNDF. The DM intake was similar for both forages at 0.76 kg/d, and CH 4 yields did not differ between forages being 22.8 and 23.8 g CH 4/kg DM intake for chicory and ryegrass, respectively. In vitro incubations of chicory and perennial ryegrass in the vegetative or mature states had similar CH 4 yields. Despite large differences in chemical composition, especially aNDF, chicory and ryegrass had similar CH 4 yields in vitro and in vivo. Chicory is not a viable alternative to perennial ryegrass for mitigating CH 4 in pastoral based sheep production systems.
